Subscribe to Multiple Event Types

Configure a single Subscription to receive events of multiple types.

Prerequisites

• You have the Eventing module in your Kyma cluster.
• You have access to Kyma dashboard. Alternatively, if you prefer CLI, you need kubectl and curl.
• Optionally, you have the CloudEvents Conformance Tool for publishing events.
• You have an inline Function as event sink (see Create and Modify an Inline Function).

TIP

Use Istio sidecar proxies for reliability, observability, and security (see Istio Service Mesh).

Context

To subscribe to multiple events, you need a Subscription custom resource (CR). The following example shows how to subscribe to events of two types: order.received.v1 and order.changed.v1.

If you want to subscribe to more event types, add more types to your subscription.

Procedure

1. Create a subscription with multiple event types.

   • In Kyma dashboard, find the default namespace, go to Configuration and create a Subscription with the following parameters:

     • Subscription name: lastorder-sub
     • Types: order.received.v1 and order.changed.v1
     • Service: lastorder (the sink is populated automatically)
     • Type matching:: standard
     • Source: myapp

   • With kubectl, run:

     cat <<EOF | kubectl apply -f -
      apiVersion: eventing.kyma-project.io/v1alpha2
      kind: Subscription
      metadata:
       name: lastorder-sub
       namespace: default
      spec:
       sink: 'http://lastorder.default.svc.cluster.local'
       source: myapp
       types:
         - order.received.v1
         - order.changed.v1
     EOF

2. Verify that the subscription is ready.

   • In Kyma dashboard, the status must be READY.
   • Alternatively, run kubectl get subscriptions lastorder-sub -o=jsonpath="{.status.ready}" and see if the response is true.

3. Port-forward the Eventing Publisher Proxy to localhost, using port 3000:

   kubectl -n kyma-system port-forward service/eventing-publisher-proxy 3000:80

4. To publish the first event (type order.received.v1) to trigger your Function, open another terminal window:

   • With the CloudEvents Conformance Tool, run:

     cloudevents send http://localhost:3000/publish \
        --type order.received.v1 \
        --id cc99dcdd-6f6d-43d6-afef-d024eb276584 \
        --source myapp \
        --datacontenttype application/json \
        --data "{\"orderCode\":\"3211213\", \"orderStatus\":\"received\"}" \
        --yaml

   • With curl, run:

     curl -v -X POST \
        -H "ce-specversion: 1.0" \
        -H "ce-type: order.received.v1" \
        -H "ce-source: myapp" \
        -H "ce-eventtypeversion: v1" \
        -H "ce-id: cc99dcdd-6f6d-43d6-afef-d024eb276584" \
        -H "content-type: application/json" \
        -d "{\"orderCode\":\"3211213\", \"orderStatus\":\"received\"}" \
        http://localhost:3000/publish

5. Publish the second event (type order.changed.v1) to trigger your Function.

   • With the CloudEvents Conformance Tool, run:

     cloudevents send http://localhost:3000/publish \
        --type order.changed.v1 \
        --id 94064655-7e9e-4795-97a3-81bfd497aac6 \
        --source myapp \
        --datacontenttype application/json \
        --data "{\"orderCode\":\"3211213\", \"orderStatus\":\"changed\"}" \
        --yaml

   • With curl, run:

     curl -v -X POST \
        -H "ce-specversion: 1.0" \
        -H "ce-type: order.changed.v1" \
        -H "ce-source: myapp" \
        -H "ce-eventtypeversion: v1" \
        -H "ce-id: 94064655-7e9e-4795-97a3-81bfd497aac6" \
        -H "content-type: application/json" \
        -d "{\"orderCode\":\"3211213\", \"orderStatus\":\"changed\"}" \ 
        http://localhost:3000/publish

6. To verify that the event was delivered, check the logs of the Function.

   • In Kyma dashboard, return to the view of your lastorder Function and go to Code > Replicas of the Function. Select your replica and under Containers, view the logs.

   • With kubectl, run:

     kubectl logs \
     -n default \
     -l serverless.kyma-project.io/function-name=lastorder,serverless.kyma-project.io/resource=deployment \
     -c function

Result

You see the received event in the logs:

Received event: { orderCode: '3211213', orderStatus: 'received' }
Received event: { orderCode: '3211213', orderStatus: 'changed' }